The spatial plant distribution in virtual ecosystems is usually modeled by means of artificial
life. Each plant is considered as a solitary element competing for its resources and obeying
simple rules of behavior. Clustering, that is an important clue for visual perception, is achieved
by sowing new plants close to their parents. In nature, plants aggregate to clusters that favor
plants of the same kind. We introduce an approach that encompasses plant clusters by implicit
curves. The clusters ”behave” as compact units and plants inside the cluster have higher chance
to survive. Clusters, in the contrary to individual plants, develop by grouped competition that
provides visually plausible results, more convincing than those achieved by the previously published
algorithms.